This invention relates to a new and improved wrench which is stamped from a strip of metal and has a relatively high strength and long operating life and to the method by which the wrench is made with accurately formed operating surfaces for engaging a nut or other article.
Relatively low quality wrenches are commonly stamped out of a sheet of low carbon steel. Although these wrenches are relatively inexpensive to fabricate, the operating surfaces of the wrench are soon deformed by use of the wrench so that it has to be discarded. In an effort to overcome the poor durability and quality of conventional stamped wrenches, it has been suggested that the wrench be provided with a corrugated construction in the manner disclosed in U.S. Pat. No. 3,298,260. Of course, forming the wrench with a corrugated construction increases the cost of fabricating the wrench and does not enhance the hardness and durability of the operating surfaces on the jaws of the wrench.
In order to provide a stamped wrench having jaws with relatively hard and durable operating surfaces, it has been suggested that the wrench be provided with a laminated construction with each of the laminations being formed of stainless steel in the manner disclosed in U.S. Pat. No. 3,709,073. Although the resulting wrench does have jaws with operating surfaces which are relatively hard and durable, the cost of forming this wrench is increased by the fact that the laminations must be interconnected by welds which extend along the entire outer peripheral edge of the laminations. Of course, the making of these welds increases the cost of fabricating a wrench, particularly when the laminations are made out of stainless steel which is, to some extent at least, difficult to weld.
Stamping operations have been utilized to sequentially form many different types of objects in the manner disclosed in U.S. Patent Nos. 3,442,159 and 3,531,861. However, all these prior art patents fail to disclose a method of forming a high quality stamped wrench which is integrally formed of one piece and has jaws with operating surfaces which are accurately formed and are relatively hard to withstand and forces applied to these operating surfaces during use of the wrench.